Metal coated material



April 25, 1933- L. w. CUTLER ET AL 1,905,959

METAL COATED MATERIAL Fil'ed Dec. 5, 1929 soluble adhesive.

Patented Apr. 25, 1933 UNITED STATES PAT NT OFFICE LEONARD WALTER CUTLER AND CARL ADOLPHE KLEIN, OE ENFIELD, ENGLAND, AS- SIGNORS, BY MESNE ASSIGNMENTS, IO GOODLASS WALL AND LEAD INDUSTRIES LIMITED, OF LONDON, ENGLAND METAL COATED MATERIAL Application filed December 5, 1929, Serial No; 411,955,'and in Great Britain December 14, 1928.

This invention relates to the metallizing of surfaces, that is to say, to the coating of surfaces with metals. The invention is more particularly concerned with the metallizing of paper and with the production thereby of waterproof and/or airproof metal-coated sheet-material to serve as a substitute for metal-foil and metal-sheet.

It is known to metallize paper by coating itwith metal-foil applied to the paper by means of an adhesive material interposed between the metal-foil and the paper. It is also known to metallize paper by applying metal powders to paper by means of a water- According to the present invention, a process for coating a surface with a metal comprises distributing over the surface and causing to adhere thereto, a finely divided metal and subjecting the surface, with the finely divided metal thereon, to pressure so as to flatten out the metal particles and thereby produce a continuous metal film upon the surface. The metal applied to the surface must, of course, be one which is sufliciently soft to enable its particles to be flattened out on the surface with the formation, as stated, of a continuous metal film upon the surface.

The invention also includes a process for coating a surface with a metal, which comprises depositing a film of an adhesive upon the surface, or impregnating the surface with an adhesive, distributing over the surface car rying the adhesive, with the latter in an ad herent condition, a finely divided metal, and subjecting the surface with the finely divided metal thereon to pressure so as to flatten out the metal particles and thereby produce a continuous metal film upon the surface. The

reference herein to impregnating the surface,

processes "for the deposition of metals..,

still further feature, thereforethe surface coated may be a sheet cellulose material, for

example paper. v a 1 r The inventionincludes, moreover, a process of manufacture of waterproof metale coated paper as above set forth, wherein the adhesive is a mixture of a hard high-meltingpoint bitumen with a soft low-melting-point bitumen and these materials are applied to the surface in solution in a low-boilingpoint solvent (e. g. naphtha) p Y Preferably, a resinsuch for example as a hard oil-soluble phenol-formaldehyde resin is incorporated with the bitumen in the above adhesive solution. w

According to another feature of the invention, a further metal may be deposited on the metal film produced upon the surface as above, for example by any of the well-know The invention includes metal coated surfaces produced as above, and, particular, a waterproof metallized sheet-material comprising a flexible backing sheet or matrix, for example, paper, waterproofing adhesive (for example, bitumen, with or without a resinous ingredient therewith) and a metal film upon the surface of one or. both sides sheet, which film has been produced by apr'ocess as set forth above, and is secured to they backing sheet or matrix by the adhesive, with or without a further metal-coating deposited upon the first.

The invention further includes in this connection, a waterproof metallized sheet-material as set forth above, wherein the adhesive permeates the body of the backing sheet or matrix and renders it waterproofein order that the sheet may be exposed to moisture or immersed in Water. I v

The invention will now I be described in greater detail as applied to the manufacture of lead-coated paper to serve as a substitute for lead-foil. It is to beunderstood, however, that the invention is not limited to this of the backing v,

by weight of soft bitumen (melting point 65 C.7 0 0.: Dow penetration number at 25 C. 2030; and ductility at 25 C. greater than 5 cm.) 30 parts by weight of hard bitumen (melting point 110 to 125 C.: Dow penetration number at 25 C. about 5; and ductility at 25 C. nil) and 10 parts by weight of the hard oil-soluble synthetic resin known under the trade name Albertol, these three ingredients being fused together and dissolved in naphtha. The temperature of the impregnating adhesive solution is preferably slightly above room temperature. The impregnating conditions are so adjusted that the paper is thoroughly impregnated through its substance with the adhesive solution prior to its exit from the impregnating ath.

The adhesive-impregnat ed paper is led from the impregnating bath over' a pair of rollers 3, 4' which have the efiect of controlling the distribution and thickness of the films'of excess adhesive adhering to the surfaces of the paper as the latter passes on to a drying chamber 5.

During the passage of the paper through the drying chamber the solvent is evaporated from the adhesive carried by the paper to such anextent that the adhesive is brought to an apparently dry or non-adherent condi-- tion. he drying chamber to this end comprises a chamber through which a current of warm air is assed. The temperature of the air is not raised higher thanis necessary to produce the desired evaporation of the solvent and preferably should not exceed about 5060 C. In practice, satisfactor results have been obtained with air at about 30 C. If the temperature of the drying step be much aboi e the temperatures stated, there is a tendency for the final metallized paper product to be undesirably brittle, due, apparently, to the fact that the material of the paper itself is dehydrated in the drying process.

The paper, with the adhesive earned by it thus in an apparently dry condition, is reeled at 6 in readiness for the application of the metal to its surfaces.

The metal-coating operation will now be described. The bituminized paper from the reel 6 isslowly drawn through a machine which distributes finely divided lead. (passing a screen of 200 meshes to the lineal inch) For this purpose a web of paper over the surfaces of bothsides of the paper simultaneously.

This machine comprises two oppositely travelling endless belts 7, 8 horizontally disposed face to face and in close proximity to one another as shown in the drawing. The

web of bituminized paper is fed continuously through the space between the opposite belts 7, 8 in the direction shown by the arrows. The belts sandwich the paper web between them, but, moving in opposite directions and travelling at the same speed, they do not prevent the feeding of the paper web through the space between them. It will be apreciated that there. is a rubbing action between the belts and the opposed surfaces of the paper as the latter is drawn through the space between the belts.

The travelling belts are enclosed within the chamber 11 and the temperature of the atmosphere within this chamber is maintained at about 60 to C. The raised temperature obtaining the chamber 11 has the effect of softening the bitumen films on the paper web as the paper web passes through the space between the belts 7, 8.

The lower belt extends beyond the upper belt at one end 9 as shown and at this end travels towards the interfaces between the belts and the paper web. Situated above the belts 8 at that end at which it extends beyond the belt 7 is a feed hopper 10 containing finely divided lead of the mesh stated. This hopperis adapted to deliver a continuous supply of finely divided lead across the width of the projecting end 9 of the moving belt 8, with the result that the portion 9 of the belt as it moves towards the interface between the belt and the paper becomes covered with a layer of finely divided lead. As the belt moves on, after this layer of lead has reached said interface, the lead becomes transferred from the belt to the film of bitumen upon the surface of the paper web, and the paper passes on, with the metal adhering to its surface, over a guide roller 12, and so, out of the machine at 13.

As will be appreciated, the projecting portion 9 of the lower belt constitutes in effect a conveyor for continuously feeding finely divided lead to the interface between the lower belt and the underside of the paper web. In a. similar way, at the other end of the machine the paper web itself is made to convey continuous supply of finely divided lead to the interface between the upper surface of the paper web and the upper belt 7. To this end a second feed hopper 14 is provided, situated above the paper web as to deliver finely divided lead on to it just prior to its entry into the space between the belts 7, 8.

Arranged beneath the belts is a collecting tray 15 for collecting finely divided lead pressure to the paper and are adapted to.

flatten out the metal particles thereon, and convert the film of separate particles into a continuous metal film upon the surface of the paper. It will be appreciated that this burnishing operation takes place on both sides of the paper simultaneously. 3

If desired, the metallized paper may now be polished, and, for this purpose, after leaving the burnishing rollers, passes on between a pair of bufiing wheels 17 which apply a gloss to the metal films on the two sides of the paper.

The metal-coated paper may now be lacquered, and for this purpose passes on to felted rollers 18, 19 dipping each in a bath of lacquer and from theserollersthe paper with a film of lacquer upon each metallized surface is led through a second dr ing chamber 20 which dries the lacquer. inally, the lacquered metallized paper is reeled ready for use.

The burnishing rollers 16 should be accurately cambered and their surfaces should be polished. Moreover, it is preferred that they should be heated, for example with steam. It'is found that better results areobtained with heated rollers than with cold rollers. If desired, the bituminized paper may be passed directly from the drying chamber 5 to the metallizing chamber 11 instead of first being reeled. In this event, the drying operation may be so controlled that the bitumen film is not completely dried on leaving the drying chamber 5, but is in a semi-viscous condition ready for the application of the metal particles by the machine in the chamber 11.'

It has been found that satisfactory results are obtainable by burnishing the metal layer into a continuous metal film upon the surface of the paper, by rollin said surface with steel-shot, instead of y passing the metal-covered paper between burnishing rollers as in the example described above.

If desired, a second metal-coating can be applied to the metallized surface by assing the metallized paper a second time t rough the above process of metallization. Alternatively, said second metal coating may be applied to the first coating by electrodeposi- By the present invention metallized sheetmaterial such as paper may be produced which is both air-proof and water-proof and also possesses the true appearance of metalfoil in contrast to the appearance of paper merely covered with a layer of metal particles such as is characteristic of the surfaces which have been simply coated with metallic paints.

The metallized material which is produced according to this invention can be soldered by the employment of suitable alloys, that is to say, alloys the melting point of which is not sufficiently elevated to damage the paper 0r other backing when melted on to the sheet.

We claim a y 1. Apparatus for distributing finely-divided metal over the surface of both sides simultaneously of a continuous web of sheetmaterial carrying an adhesive, which com- 3 prises a pair of oppositely-travelling endlessbelts disposed horizontally face-to-face and in close proximity to one another, means to feed a web of sheet-material carrying adhesive continuously through the space between the belts, means to deliver finely-divided metal on to the moving web of sheet-material before it enters said space, and means to deliver a similar supply on to the lower belt before the latter reaches the interface between itself and the web of sheet material, said lower belt being extended beyond the upper belt at one end to receive this supply, and travelling towards said interface at this end, the web and the lower belt thus constituting conveyors for the metal to the interface between the belts and the web.

2. Apparatus for the production of a metallized paper web which comprises in combination a bath containing 'a thermoplastic adhesive, means to pass the web into said bath, a heated chamber, means to pass the impregnated web with a film of adhesive upon its face through the chamber to soften the adhesive, means to apply metal powder to the surface of the web, a flexible endless band travelling in contact with the web, and having a surface speed which differs from that of the paper so that a rubbing action is imparted to the paper, said band contacting with that side of the web on which the metal powder is fed, whereby the powder is flattened by the pressure of the band.

In testimony whereof we have signed our names to this specification.

LEONARD WALTER CUTLER. CARL ADOLPHE KLEIN.

tion, or by immersing the lead covered paper 

